1.Field of the Invention
The present invention relates to an image forming apparatus, and in particular, to a multi-beam image forming apparatus such as a copier or a printer that forms an image with a plurality of laser beams for improvement in image forming speed.
2.Description of the Related Art
Due to a need for printing a high-quality image with high resolution and at high speed, a multi-beam image forming apparatus, which is made to scan in parallel the surface of a drum photoconductor by a plurality of laser beams, is being tested for realization in a latest image forming apparatus of electrophotographic type. Such a multi-beam image forming apparatus has a significant technical problem in practical use. That is, the problem is how the light-and-shade difference among image lines formed by the laser beams can be harmoniously adjusted.
More specifically, in the multi-beam image forming apparatus, a distortion occurs in an electric current due to a stray capacitance existing in a driving element supplying a driving electric current to a laser diode, in its electric current passageway and the like, rendering it difficult to adjust an image density. Moreover, since a fluctuation occurs in the image density for each dot and a moire occurs in the formed image, it is difficult to solve the problem of image quality by merely adjusting the driving electric current for each laser diode.